|Do you see anything on the screen at all? If not it must be something you did.|
See if you can get into BIOS, because that doesn't use the HD at all.
Make sure everything is plugged in firmly (in case you disturbed something else while you were inside).
Not sure what this meant:
"lightly cleaned it with a peice of rubber"
Do you mean its connectors?
I would only take the HD apart as a very last resort and when I know for certain it is faulty. You might be able to slave it to another computer to see if it can be read.
Note that oxide on RAM edge connectors can sometimes cause issues which show up if the RAM gets moved slightly. Those can be cleaned with a pencil eraser and I usually pop them in and out a few times to make sure the sockets themselves are clear.
One final possibility is to make a Linux Live CD (such as Puppy Linux) on another computer. You then use the "burn an image" feature to create a CD. To run it you insert it into the drive of the dud computer then power-up. You might have to go into BIOS and set the CD drive ahead of the HD. If it works then it gives a fair amount of confidence that the RAM, PSU and motherboard are OK because it works just between RAM and the CD - not using the HD at all.
Always pop back and let us know the outcome - thanks